Electric conductor.



A. H. 6L C. D. MCCULLOCH.

ELECTRIC CONDUCTOR.

APPLICATloN FILED DEC.2,1912.

tented Feb. 20, 1917.

Fay

M6522 655 e5: (0MM J4 f4.1/

UNITED STATES PATENT OFFICE.

ALFRED H. MCCULLOCH AND CAROLINE D. MCCULLOCH, OF BOSTON, lVIASSACI-USETTS.

ELECTRIC CONDUCTOR.

Application filed December 2, 1912.

To all whom t may concern:

Be it known that we, ALFRED H. Mobili.- Looii and CAROLINE D. MCGULLOCH, citizens of the United States, residing at Boston, in the county of Sulfolk, State of Massachusetts, have invented a certain new and useful Improvement in Electric Conductors, ttc., of which the following is a specification, reference being had therein to the accompanying drawings.

The invention is an improvement in the coverings which are applied to electrical conductors, electrical cables, electrical tubing, and other products of manufacture, including conduits for air, steam, andelectrical wires. The improved coveringr may be applied for the purpose of insulation, or for prevention of chemical disintegration or fire, or for protection from mechanical wear and injury, or for the purpose of concealment, or as a finish to produce the desired surfacing, color, or appearance.

The three forms of coverings which are most generally applied at the present time toelectrical conductors, etc., are the spirally wound covering, the braided covering, and the woven covering. The spirally wound covering has the advantages of economy of material, of requiring only sirnple machinery for its application. and of being very rapidly applied. Such covering. however, as heretofore applied, has a. numloer of material drawbacks ordisadvantages. lt is liable to displacement and to separation of its turns or coils, to unwrapping, and to fraying out when exposed to certain conditions. It is ill adapted, therefore, to withstand the action of the wipers and the other treatment in waxing, polishing, and weatherprooting the same, Consequently in many cases it is superseded by the braided covering and the woven covering. These, however, in their turn have the drawback or disadvantage that both contain a far greater proportion of material than the spirally wound covering, rendering them proportionately more expensive, owing to the fact that in a braided covering one set of threads is overlaid by another, thereby making two thicknesses of threads, While in a woven cov- Specific-ation of Letters Patent.

PatentedFeb. 20, 1917.

Serial No. 734,494.

ering the warp-threads and weft-thread or threads also overlie one another in a plurality of thicknesses. ln addition, the ma chinery required for the application of braided and woven coverings is complicated and much more costly than that required for applying spirally wound coverings, and is fa r slower in its performance` of the work Aof applying coverings, so that the days output of a machine applying either a braided covering or a woven covering is very much less than that of a machine applying a spirally wound covering, and the cost of applying the covering is proportionately greater.

lVe have discovered that by combining with the turns or coils of the spirally wound covering one or more solitary lines of binding for the said turns or coils we can obviate the drawbacks or disadvantages of such form of covering, and render the spirally wound article suitable for employment in connections in which it has been found possible heretofore to employ only articles with braided or woven coverings, without noticeable increase in the amount of covering material employed, and in most cases without lessening the speed of manufacture.

ln accordance `with our invention we provide a covering comprising one or a, plurality ol spirally wound threads. yarns, wires or ta pes. and one or more solitary lines of binding for the spiral turns or coils. Preferably, each of such lines-of binding comprises a longitudinal thread` yarn. wire or tape passing in and out alternately so as to underlie one or more of the spiral turns. and then overlie one or more tl'ierreof, and so on'iu an alternating succession, the said longitudinal thread or the like thus engaging with the spiral turns in manner to bind the latter in place. Two or other small number of the longitudinal threads, etc., may be employed in a line of binding. vThe interlacing thread or the like binds the spiral winding firmly upon the object covered. so that the winding cannot unwrap, and holds-the turns thereof so that they cannot separate from one another and so as to prevent portions of the covering from slipping lengthwise upon the wire or other object. away from adjoining' portions as sometimes occurs when covered wires are forced through narrow holes or other passages.

()ur invention is illustrated in the accompairving drawings, in which- Figure 1 represents a short length ot wire l'uiving applied thereto a spirally-wound covering embodyingr the invention.

Figs. 2 to 1t) show other einbodiments olI the invention.

llavingr reference to the dra winlosrw ln the respective emlauliuunts o'l the in vention the central wire is marked 1 in cach instance, ils coat-iupr ole insulating material beingl marked l, tlul spirally-wound f foverings are marked 2, and the threads which are employed for the solitary lines of binding are marked 3. Fig. l shows a single binding` thread engaged with the turns ot' the spirally-wound covering' by passing over a single spiral turn, then under a single-spiral turn, then' over a single turn, and so on successively. Fig. 2 shows a single binding thread which passes over two turns of the spirally-wound covering, then under two turns thereof, and so on successively. Fig. 3- shows a single binding thread passing' over and under three spiral turns in alternating succession. More than one wire may be inclosed within the cover- The number ot' separate threads wound spirally in adjoining` coils may be increased as high as is found practicable, and the number ot` turns over and under which the binding thread passes may be greater than here shown. Fig. 4 shows a solitary line of binding?r produced by the. employmentv of two binding' threads which oppose each other in their engagement with lthe spiral turns, so that one thereof passes over four turns while the other passes under such turns, and vice versa. Fig. 5 shows the spirally-wound covering,` bound by two solitary lines otbinding located diametrically opposite. each other.

The function of the longitudinal binding thread or threads is not that of covering'the inclosed wire. but is that ot binding in place thesuccessive turns of the spirally wound wrapping which constitutes the covering. The said longitiulinal binding' thread or threads conveniently isxor arel utilized to serve as a marker or n'iai'kers for distinguishingjr the particular wire, by being made ot color or material diti'erent trom that of the spirall'v-wound covering'. Ordinarily the longitudinal binding' threads may consist of the smallest number ot' threads and. the least quantity of material that will fultil the requirements ot their service as binders, and as markers when they are utilized as such. For many purposes a single longitudinal binding thread will suffice for both binder and marker. l'n some cases, the binding threads may besufliciently coarse to produce a prominent line along the covering' that can be felt, as in Figs. (3 and 7, to thus enable the wires to be distinguished by the sense of touch.

We do not contine ourselves to the use. ol` the saine material tor the spirally wound covering' and thc binding, and while we have referred to binding threads we conlcmplaie the use ol' threads, yarns, tapes, or wires as circumstances may reduire. In a rase iu which two lmigitudinal binding' lhreads are employed, wc sometimes vary their distinguishing charactcristics by the use ol'. dissimilar materials, colors, sizes, or shapes, so that the two longitudinal threads will present a contrast between themselves to the sight and to the touch. While in most cases the binding thread is extended in a straight line parallel with the axis of the wire, in some cases we cause it to extend in a helical direction, as in Fig. 8. We have shown but a single 'covering layer in the case of each of the illustrated embodiments of the inventioi'i, but in practice we shall apply two or more layers, one outside the other. in all cases in which a plurality of layers is required.

Figs. 9 and 10 .illustrate modiiications in each of which the longitudinal binding thread loops around the spiral turns or coils ol? the covering. In Fig. 9 the portions of sa id binding' thread between successive loops underlie the turns or coils, and the loops tace outward from the wire. lin Fig. l0 the corresponding portions lie outside the turns or coils`r and the .loops face inward toward the wire. Both ot' these n'iodiiications pro ride for more positively locking' the spiral turns or coils in place. he binding threads ot these inodilications furnish markers which may serve either visually or as mechanical projections, and the outwardly facing;q loops ol Fie'. t) may occur at any desired periodic intervalsl to serve for purposes of differentiating identification.

What we claim as our invention is l. The herein describedl spirally-wound covering', with all the turns or coils in a layer wral'iped or wound in the saine direction, and havin,"r combined with the spiral turns or coils comprising such layer a` solitary line ol" bimling ior such turns or coils.

The herein described spirallyovmind covering` with all the turns or coils in a. layer wrapped or wound in the saine direction and having' combined with the spiral turns or coils comprising such layer. a solitaiv line ot binding consisting' or a longitudinal thread or threads engaging with successive turns or coils.

3. The herein described spirally-'\vound covering', with all the turns or coils in a layer Wrapped or wound in the same direc- In testimony whereof We aix our signation, und having combined with the Spiral tures, in presence oi two witnesses.

turns or Coils constituting the said layer a ALFRED H. MCCULLOCH. marker consisting of a longitudinal thiezid CAROLINE D. MCCULLOCH. or the like engaged with the said turns or VitneeseS:

coils. `.ind constituting the chief longitudinal NATHAN B. DAY,

binding therefor. CHAS. F. RANDALL. 

